package edu.whu.notepal.controller;

import cn.hutool.core.lang.UUID;
import edu.whu.notepal.dto.Result;
import lombok.Cleanup;
import lombok.SneakyThrows;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.system.ApplicationHome;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;

/**
 * @description 文件上传和下载
 * @author 陈磊
 */
@RestController
@RequestMapping("/common")
@Slf4j
public class CommonController {

    @Value("${file.path}")
    private String basePath;

    /**
     * 文件上传
     *
     * @param file 文件
     * @return 文件重命名后
     */
    @SneakyThrows(value = IOException.class)
    @PostMapping("/upload")
    public Result upload(MultipartFile file) {
        //file是一个临时文件，需要转存到指定位置，否则本次请求完成后临时文件会删除
        log.info(file.toString());

        //原始文件名
        String originalFilename = file.getOriginalFilename();
        String suffix = originalFilename.substring(originalFilename.lastIndexOf("."));

        //使用UUID重新生成文件名，防止文件名称重复造成文件覆盖
        String fileName = UUID.randomUUID().toString(true) + suffix;

        File dir = new File(basePath);
        //判断当前目录是否存在
        if (!dir.exists()) {
            //目录不存在，需要创建
            dir.mkdirs();
        }
        file.transferTo(new File(basePath + fileName));
        return Result.success(fileName);
    }

    /**
     * 文件下载
     * @param name 文件名
     * @param response 响应
     */
    @GetMapping("/download")
    @SneakyThrows
    public void download(String name, HttpServletResponse response) {
        //获取根目录
        ApplicationHome h = new ApplicationHome(getClass());
        log.info("请求下载{}", name);
        @Cleanup FileInputStream fileInputStream = new FileInputStream(new File(basePath + name));

        //输出流，通过输出流将文件写回浏览器
        @Cleanup ServletOutputStream outputStream = response.getOutputStream();

        response.setContentType("image/jpeg");

        int len = 0;
        byte[] bytes = new byte[1024];
        while ((len = fileInputStream.read(bytes)) != -1) {
            outputStream.write(bytes, 0, len);
            outputStream.flush();
        }
    }
}